Rubio-Govea, R.; Opis-Basilio, A.; Torres, A.; Sánchez, M.; Ray, K.; Mazzio, K.A.: Unveiling the Spectroscopic Signatures of Poly(3,4-ethylenedioxythiophene) by Controlling Polaron and Bipolaron Concentrations. The Journal of Physical Chemistry C 128 (2024), p. 18612-18621
10.1021/acs.jpcc.4c05602
Open Access Version
Abstract:
The electronic and optical properties of conductive polymers (CPs) are related to the formation of polarons and bipolarons localized along the polymer backbone. Their concen- tration is affected by the conformational and morphological features of the CPs, making it crucial to understand how they are affected by chain conformation and π-electron delocalization. In this work, we studied the modulation of the concentration of polarons and bipolarons in PEDOT:PSS after post-treatment with hydrazine and H2SO4, which influence the optical and electronic properties. Through a combination of electron spin resonance spectroscopy, UV−vis−NIR spectroscopy, Raman spectroscopy, and conductivity measurements, we evaluate changes in the properties of PEDOT, which are related to the chain conformation and π-electron delocalization within the polymer backbone. We present experimental evidence supporting the recently revised interpretation of the UV−vis−NIR spectrum of PEDOT:PSS, and through a combination of theoretical and experimental analysis, we propose a new interpretation of the Raman spectrum of PEDOT:PSS. Furthermore, we provide the first experimental evidence of the presence of polaron pairt.